Copper and copper base alloys



March 17, 1936. c. H. DAVIS COPPER AND COPPER BASE ALLOYS Filed Oct. 13,1934 216 920 M g m ATTORNEYS Patented Mar. 17, 1936 UNITED STATES PATENTOFFICE COPPER AND COPPER BASE ALLOYS Application October 13, 1934,Serial No. 748,193

1 2 Claims.

This invention relates to articles made of copper and copper base alloysimproved with respect to resistance to corrosion or intercrystallineparting in the metal, particularly in steam, by the addition of acertain amount of cadmium.

It has been found in certain types of steam service, especially attemperatures above 212 F. C.) and pressures above atmospheric, that thesteam and (or) gases commonly associated with steam in ordinarymanufacturing or commerce cause certain copper base alloys todisintegrate or crack.

Notable failures of copper and copper base alloys have occured while inuse, as portions of expansion joints in the steam lines in large cities,such as New York and Boston. The early or unexpected failure of copperor copper base alloys in these locations is a. serious menace tocommerce and health. An intensive study of the causes of such failuresin copper base alloys was initiated with'the result that by a novel'method of testing in steam, certain alloys have been discovered to beparticularly resistant to the action of steam at elevated temperatures.

The disintegrating action of the steam or gases in the steam mentionedin the previous paragraphs is especially pronounced at the boundaries ofthe grains of the alloys; separating said grains or crystals bydestroying the cohesion and bond that normally holds the alloy crystalstogether in a strong, unified mass. Certain copper base alloys, whenunder stress, or when alternately stressed and unstressed, have beenshown more susceptible to this disintegrating action of steam and (or)gases in steam than other copper base alloys. Commercially pure copperitself is susceptible to this action just described and fails quicklyunder the higher unit stresses.

. The effect of steam at elevated temperatures upon copper and certaincopper base alloys is known to the engineers in charge of aforesaidsteam lines and to certain of the engineering and metallurgicalprofessions, but it has beenfurther demonstrated in a novel method oflaboratory test.

Wires of copper and many copper base alloys have been subjected whileunder stress, or while alternately stressed and unstressed, to theaction of steam. It was found by said tests that representative wroughtcopper base alloys from the following alloy systems, while under stress,are susceptible to a greater or less degree to the disintegrating actionof steam, and this indicates the remaining alloys of these systems arealso so susceptible to this disintegrating action. These systemsinclude, in addition to the commercially pure copper:

Commercial copper-silicon alloys up to at least 5 indicates thatpractically all copper base alloys are improved at least to some extentby the presence of cadmium in the alloy with respect to resistance tocorrosion in steam.

The tests were made in a cylindrical steam chamber with normal pressurepounds per sq. in. gauge pressure, equivalent to a temperature of aboutC. The steam was analyzed and the impurities determined. The copper basealloy specimens were in the form of .036" diameter wire and these passedthrough glands sealed with asbestos packing in each head of the cham- 85her so that a load of any size might be applied to stress the wires. Theloads varied from no load up to 80% ofthe ultimate strength ofthespecimens. Tests made under intermediate loads, such as 5%, 10%, 20%,30%, 40%, etc. of the ultimate strength of the specimens revealed thatthe length of life of the specimens under test in steam variedproportiontally with the amount of load or stress applied during thetest. Hence, tests were conducted at stresses both under and over theyield point, elastic limit and (or) proportional limit of manyspecimens. The usual procedure was to keep the steam turned on at alltimes but to remove the load for a certain period of the specimens andextending inward until the 66 remaining cross-section of sound metalfractured because of the increased unit stress.

Another type of failure was discovered where the grains parted in theinterior of the specimens with no apparent connection with the surfaces.Certain specimens failed by one or the other of these types ofintergranularseparation, while others failed by a combination of the twotypes of parting.

In order to present concrete evidence of the behavior of severalselected copper base alloys in the testing apparatus described in theabove paragraphs, examples of these alloys are now listed. The specimenswere in the steam chamber in about 130 lbs. per sq. in. steam pressure(180 C.) and each specimen was stressed individually to of its ultimatetensile strength.

The above actual steam tests and many other similar tests havedemonstrated the superiority In many instances apparatus fabricated ofthese cadmium-bearing copper base alloys may need to be joined bywelding. It has been found that such welds can be and are preferablymade from similar cadmium-bearing welding, or filler rods, for it isimportant that welding joints be as resistant to the disintegratingaction of steam as the metals welded.

A characteristic of a number of these alloys is a reddish surface filmnoticeable after annealing or heating, especially on the surface of thelighter nickel-bearing alloys. This film appears to afford someprotection against intercrystalline parting or corrosion.

In casting the aforedescribed copper base cadmium-bearing alloys thecadmium may be added as the metal or in any other suitable form ofalloy. In other words it may be added as in usual casting shop practice.A satisfactory way is to Results of tests in steam of various copper baralloys each stressed to 80% of its ultimate strength Alloy Failed athours under Cuv Sn Cd Si Mn Ni Al Zn stress of the cadmium-bearingcopper base alloys under stress in steam. My tests show other elementssuch as manganese, nickel, tin and arsenic, and combinations of theseelements materially aid in preventing or inhibiting the action of steamand/or-gases in steam on copper and copper base alloys, and although werecognize the beneficial effects of the presence in certain copper basealloys for service in steam of such elements as manganese, nickel, tinand arsenic, I have discovered and demonstrated that cadmium is the mostbeneficial in a great many instances, and even improves the corrosionresistance to steam and/or gases when used with these elements. Thefollowing are examples.

Cadmium added to commercial copper Cadmium added to copper-tin alloysCadmium added to copper-nickel-aluminum alloys Cadmium added tocopper-nickel-aluminumzinc alloys Cadmium added tocopper-silicon-manganese alloys Cadmium added to copper-nickel-siliconalloys Cadmium added to copper-nickel alloys Cadmium added tocopper-silicon alloys Cadmium added to copper-aluminum alloys Thecadmium is ordinarily in amount from 0.01% to approximately 1.50% of thealloy, although it may be as high as 3%, if desired."

add it as master alloy, say for example of copper and 10% cadmium. Theresultant alloy may be cast in any suitable molds. Said castings maythen be rolled, forged, 'hammered, drawn, extruded, etc. either hot orcold, and in most instances both hot and cold, into various forms, suchas sheets, bars, rods, wire tube, and the like, by methods now wellknown and practiced in the copper alloy industry.

Some of the. uses to which the cadmium-bearing copper base alloys may beput include'conductors of electricity and of heat, particularly wheresteam is present, condenser tubes, expansion joints and the devices ofthe sort in steam lines, steam regulating devices or controls,'corrugated seamless tubes, and flexible metal hose, bellows, diaphragmsand other parts of steam or water controls and power devices, valves ortraps, heater tubes, steam conductors, and reservoirs, tanks, vats andother containers of liquids at steaming temperatures, steam turbineblades and other parts, and all apparatus particularly designed forsteam service or to resist the corrosive and disintegrating action ofsteam.

In the accompanying drawing are shown examples of various articles foruse in steam and hot water service which are greatly improved for thisservice by my invention, as their life both stressed and unstressed whenused in contact with steam or hot water is greatly increased by the useof these alloys containing cadmium as this greatly action of the steamand hot water and/or gases in steam.

In this drawing Fig. 1 is a longitudinal section of a pipe, tube orconductor which may be used for conducting steam and hot water;

Fig. 2 is a cross section thereof;

Fig. 3 is a longitudinal section of a portion of a bellows which may beused for expansion joints, controlled or regulating devices, etc. forsteam and hot water service;

Fig. 4 is a cross section thereof;

Fig. 5 is a cross section of cupped, drawn or formed metal sheetstelescoping each other and adapted for use in steam service and steamregulating devices;

Fig. 6 is a top plan view thereof;

Fig. 7 is a longitudinal section of an annular, corrugated, seamlesstube which may be used in steam or hot water systems;

Fig. 8 is a transverse section thereof;

Fig. 9 is a partial longitudinal section and a partial side elevation ofanother type of a corrugated seamless tube;

Fig. 10 is a. transverse section thereof;

Fig. 11 is a side elevation of a boiler or container for steam or hotwater;

Fig. 12 is a transverse section of a flexible diaphra Fig. 13 is a topplan view thereof;

Fig. 14 is a top section of a plane diaphragm;

Fig. 15 is a plan view thereof;

Fig. 16 is a partial longitudinal section and partial side elevation ofanother form of flexible metal tube or hose;

Fig. 17 is a transverse section thereof;

Fig. 18 is a flat sheet metal piece;

Fig. '19 is a similar strip curved to any desired shape; and

Fig. 20 is a perspective view of a tank or con- The device of Fig. 5comprises two cupped sections 23 and 24 cupped, drawn or formed fromsheet metal sheets of this alloy and are assembled in telescopingrelation so as to adjust the position under various pressures, etc. inregulating devices for steam and hot water systems- They may beconnected to the system by suitable pipe connections to the nipples 25.

The corrugated seamless tube 26 of Fig. 7 is made of thin flexible metaland may be used for conducting steam and water and other similar uses.The corrugations in this particular form are annular.

The seamless tube 21 of Figs. 9 and 10 is simi-' larly constructedexcept that the spirals rim helioally and may be used for conductingsteam and other uses the same as the tubes of Figs. 7 and 8.

The element 28 in Fig. 11 shows diagrammatically a boiler, tank or othercontainer for steam or hot water, and may be constructed in any desiredmanner, such as riveted or welded sheets, heads, etc.

The diaphragm 29 of Figs. 12 and 13 is made from a thin flexible sheetof metal alloy and may be corrugated as indicated at 30 and may be usedfor regulating devices, etc.

The diaphragm 3| of Figs. 14 and 15 is substantially the same exceptthat it is plain instead of corrugated.

In Figs. 16 and 17 is shown a common type of helically wound interlockedflexible metal hose it being formed of a strip 32 shaped at one side bybending inwardly and laterally as shown at 33 and placed betweenoutwardly bent portion 34 of the opposite edge of the next adjacentconvolution, so that these convolutions are inter locked and are capableof certain relative movement to permit flexingof the tube. They may beused for conducting steam or hot water between relatively movableelements of a system and in other locations as found desirable.

The flat plate 35 of Fig. 18 may be used for any desirable purpose orfor making various elements of the steam or hot water system.

The same is true of the irregular shape 36 of Fig. 19.

The tank 31 shown in Fig. 20 may be of any suitable construction thatshown having side walls 38 and end walls 39 and a bottom wall not shown.

These elements illustrated are shown merely as examples of the largenumber of elements which may be improved by my invention whereby theyhave increased resistance to corrostion and disintegration when used incontact with steam and hot water.

In addition to imparting the resistance to corrosion and disintegrationthe cadmium also imparts resistance to creep" (gradual elongation) understress even at the elevated temperatures met with in use with hot waterand steam.

My preferred invention is therefore an alloy intended principally forservice in steam and characterized by the presence of cadmium from 0.01to approximately 3.0%. This alloy is usually wrought, either hot orcold, or both, but may be used in the cast condition or in a weld orbraze.

Having thus set forth the nature of my invention, what I claim is:

1. An element for use in conveying or distributing steam or hot waterfabricated from copper or a cop er base alloy in which the tendency tointercrys alline parting in the metal is reduced by the incorporation ofa small percentage of cad- CHARLES H. DAVIS. 3

CERTIFICATE OE CORRECTION.

Patent No. 2,034,561, March 1'7, 1,9256e CHARLES H. DAVIS.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second column, line 25, for the word inc'ricates" read indicate; line42, for "proportiontally" read proportionally. The table, page 2, shouldbe inserted between lines 17 and 18 of column 1; in the heading to thetable, for "bar" read base, and in the table, test No. 18, strike outthe dotted line in the last column and insert instead a zero; and. thatthe said Letters Patent should be read with these corrections thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 8th day of December, A. D. 1956,

Miriam-y Van Arsdale (Seal) Acting Commissioner of Patents,

CERTIFICATE OF CORRECTION.

Patent we. 2,054,561. March 1'7, 1936.

CHARLES H. DAVIS.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second column, line 23, for the word "indicates" read indicate; line 42,for "proportiontally" read proportionally; page 2, second column, line51, for "wire tube" read wire, tubes; same page, the table should beinserted between lines 1'? and 18 of column 1; in the heading to thetable, in the table, test No. 18, strike out the dotted line in the lastcolumn and insert instead a zero; page 3, second column, line 61, claim2, strike out 'Eht article "a"; and that the said Letters Patent shouldbe read with these corre ticns therein that the same may conform to therecord of the case in the Pat ent Office.

This Certificate of Correction issued in lieu of Certificate ofCorrection issued December 8, 1936 so as to correct an error therein.

Signed. and sealed this 5th day of January, A. D. 195?.

: :Benfyyan Arena-1e (Seal) Acting Commissioner of Patents.

for "bar" read base, and

